1. Field of the Invention
This invention relates to orthopedic diagnostic techniques and more particularly pertains to a non-invasive, non-irradiating method of confirming suspected bone fractures.
2. Brief Description of the Prior Art
Bone fractures are most often diagnosed or confirmed radiographically. Certain fractures in certain bones are, however, hard to detect via an X-ray series and may require additional, costly and time consuming procedures to confirm. Often such procedures call for further exposure to radiation which is, of course, preferably avoided or minimized.
A fracture of the carpal scaphoid may be particularly hard to detect and is susceptible to misdiagnosis. The unique distal to proximal blood supply of the carpal scaphoid and the major shear stresses imposed upon it by its linkage role in carpal kinematics predispose scaphoid fractures to complications. Fracture non-unions of the scaphoid may result in a post-traumatic arthritis many years after the injury which is disabling due to the scaphoid's articulation with the distal radius and four of the seven carpal bones. It is therefore extremely important that such a fracture be promptly and correctly diagnosed to ensure proper treatment.
Presently, post-trauma patients with tenderness in the anatomic snuffbox between the extensor pollicus longus and extensor pollicus brevis are placed in thumb spica casts despite negative plain film X-rays The patient is asked to return in ten to fourteen days for repeat X-rays and an examination out of plaster. If there is a negative clinical exam and normal X-rays the injury is treated as a resolving wrist sprain. If a fracture is not noted on the delayed X-rays and the patient continues to have tenderness in the anatomic "snuffbox", the patient is immobilized in another thumb spica cast.
Technetium bone scans have been advocated for the early diagnosis of scaphoid fractures to avoid the 2-3 week delay required by conventional techniques. Such bones scans have been reported to be 100% sensitive in the diagnosis of scaphoid fractures at 72 hours. In an effort to decrease costs and radiation exposures it has been concluded that scans should be performed after 10-14 days if the patient was clinically positive and radiographically negative. This was found to spare approximately 70% of the patients from requiring a bone scan. The radiation dose to the patient's hands is minimal although the bladder receives 2.5-5 Rads.
Bone scans have been described as 100% sensitive and 75% specific in detecting scaphoid fractures. False positives include arthrosis, tenosynovitis, cysts, unfused epiphysis scapholunate dislocations and Kienbock's disease. In addition, the trapezoid/trapezium region has demonstrated a disproportionate amount of positive increased uptake results with no fractures revealed on delayed X-rays.
In light of these shortcomings, an improved method of diagnosing occult fractures such as fractures of the carpal scaphoid is therefore called for that provides a fast, simple, reliable and inexpensive means of confirming suspected fractures.